This invention relates to drip coffeemakers and in particular to a hot water generator assembly for the coffeemakers.
Conventional automatic drip-type coffeemakers have enjoyed widespread use and commercial acceptance. Drip coffeemakers are a very popular consumer small appliance. Such coffeemakers typically include a reservoir for containing water, a hot water generator to heat the water, a spreader for receiving the hot water and a container or basket ("brew basket") adapted to hold the coffee grind (generally in a filter) and to receive the heated water. The heated water is directed by the spreader onto the coffee grind contained in the brew basket. The brewed coffee is drained from the brew basket through an aperture located at the bottom thereof into a carafe supported on a base portion of the housing.
Many commercially available coffeemakers have a heating means associated with the carafe supporting base portion to maintain the coffee in the carafe warm for a period of time after it has been brewed. In many such coffeemakers, the same heater used to generate the hot water for brewing the coffee is also used for maintaining the coffee warm in the carafe. In other models of coffeemakers, a first heater is used to generate the hot water and a second heater is employed as a "keeps warm" heater.
Most drip-type coffeemakers employ a cycling thermostat to control the operation of the heating means for the hot water generator. Typically, the thermostat opens when it senses that the temperature of the hot water generator has reached a predetermined level and the thermostat will close when the coffeemaker is connected to a source of electrical power and the temperature of the hot water generator falls below a predetermined level.
Particularly in those coffeemakers utilizing a separate "keeps warm" heater, it is desirable that the heating means for the hot water generator be rendered inoperable for as long a period of time as possible by maintaining the thermostat open. By reducing cycling of the thermostat, the operating life of the thermostat will be extended. Further, by keeping the thermostat open for a longer period of time, the heat transferred to other parts of the coffeemaker from the hot water generator will be minimized. This will also have a positive effect on the performance and operating life of the coffeemaker.
It has also been found that many commercially available present hot water generators do not provide for consistent hot water generation. To achieve full-flavored extraction of the coffee from the coffee grind, the hot water delivered to the brew basket should be at a consistent, relatively high temperature. The temperature of the water exiting the hot water generator should exceed 200.degree. F., but be below 212.degree. F.
It is accordingly an object of this invention to provide a coffeemaker which is efficient in operation by providing consistent temperature hot water to the brew basket and by maintaining the thermostat associated with the heating means for the hot water generator open for relatively long periods of time.